Karami Asma Mohammad, Bani Ali, Pourkazemi Mohammad, Ghasemi Mohades, Kania Per Walter, Buchmann Kurt
Department of Biology, Faculty of Science, University of Guilan, Rasht 4199613776, Iran.
Dis Aquat Organ. 2018 Jun 4;128(3):187-201. doi: 10.3354/dao03231.
Caspian trout Salmo trutta caspius is an endangered subspecies of brown trout Salmo trutta which is native to the Caspian Sea. Restocking programmes have been established, but recent introduction of the rhabdovirus viral haemorrhagic septicaemia virus (VHSV) into Iranian rainbow trout farms connected to waterbodies supporting wild Caspian trout may represent an additional threat to the declining stock. The susceptibility of wild and cultured populations of this endemic subspecies was demonstrated by performing controlled VHSV infection experiments (both by bath and injection challenges). Subsequently, VHSV infection in exposed fish was confirmed (CPE and quantitative PCR), virus levels were measured, and regulation of immune genes in exposed fish was investigated with a focus on the genes encoding IL-8, IFNγ, TGFβ, TNFα, SAA, C3-4, CD8α, IgM, MHC I, MHC II, iNOS and IGF-1. The presence of IgM-, CD8α- and MHC II-positive cells in host organs was visualized by immunohistochemistry. Both wild and cultured trout strains proved to be VHSV-susceptible following experimental challenge, but the mortality curves and associated regulation of immune-related genes differed between the 2 trout types. Implications of the results for future management of Caspian trout populations are discussed.
里海鳟鱼（Salmo trutta caspius）是褐鳟（Salmo trutta）的一个濒危亚种，原产于里海。目前已制定了放流计划，但最近弹状病毒——病毒性出血性败血症病毒（VHSV）传入与支持野生里海鳟鱼的水体相连的伊朗虹鳟养殖场，这可能对数量不断减少的里海鳟鱼种群构成额外威胁。通过进行对照VHSV感染实验（包括浸浴和注射攻毒），证明了这种特有亚种的野生种群和养殖种群均具有易感性。随后，对暴露鱼体中的VHSV感染进行了确认（细胞病变效应和定量PCR），测量了病毒水平，并研究了暴露鱼体中免疫基因的调控情况，重点关注编码白细胞介素-8（IL-8）、γ干扰素（IFNγ）、转化生长因子β（TGFβ）、肿瘤坏死因子α（TNFα）、血清淀粉样蛋白A（SAA）、补体C3-4、CD8α、免疫球蛋白M（IgM）、主要组织相容性复合体I类（MHC I）、主要组织相容性复合体II类（MHC II）、诱导型一氧化氮合酶（iNOS）和胰岛素样生长因子-1（IGF-1）的基因。通过免疫组织化学观察宿主器官中IgM、CD8α和MHC II阳性细胞的存在情况。实验攻毒后，野生和养殖的鳟鱼品系均被证明对VHSV易感，但两种鳟鱼类型的死亡率曲线和免疫相关基因的相关调控存在差异。本文讨论了这些结果对里海鳟鱼种群未来管理的意义。
